Scirtothrips quadriseta sp. nov.

[Figs 19, 29, 46, 56]

Female macroptera. Colour: Dark brown, head and tergites IX­X darkest; antecostal ridges on tergites III­VIII dark across full width of segments, on sternites III­VII shaded full width of segments; forewings uniformly light brown; antennal segments brown, I and III – VIII paler than head.

Structure: Vertex with closely spaced and transversely anastomosing striae, but ocellar region without lines of sculpturing; bases of ocellar setae pair III arising within ocellar triangle, separated approximately by the length of these setae, arising anterior to tangent between anterior margins of posterior ocelli; two pairs of post­ocular setae. Pronotum with transverse striae closely spaced but irregular; 4­8 anteromarginal setae, 15­22 discal setae; 4 pairs of posteromarginal setae, S2 variable but no more than 1.5 times as long as S1, S3 subequal to S1. Metanotum transversely reticulate anteriorly, equiangular medially, but longitudinally reticulate on posterior half, median setae posterior to margin. Forewing scale with 3­5 marginal setae; first vein with 10 – 14 setae, 1­4+1­5+1­3+1­2+1­2+0­1+0­ 1+0­1; second vein 2­4 setae; posteromarginal fringe cilia mainly straight but wavy near base of wing. Tergites III­IV median setae short, distance between bases at least 1.25 times the length of these setae; tergal microtrichial fields with 3 discal setae; VIII with no discal microtrichia medially, posteromarginal comb complete; tergite IX with discal microtrichia on posterior half. Sternites III­VI usually with 4 pairs of posteromarginal setae; microtrichial fields reduced to 5 or 6 rows of microtrichia anterolaterally.

Measurements of holotype female. Body length 1050. Head, length 70; width 150; p.o. S1 15. Pronotum, length 95; width 190; posteromarginal setae S1 12, S2 20. Forewing length 650. Antennal segments III – VI, 38, 35, 35, 38.

Holotype Female. Western Australia, 20 km south of Yalgoo, from Acacia aneura [Leguminosae], 26.iv.1997 (LAM 3230). Paratypes: 9 females collected with holotype; Western Australia, 6 km north of Meekatharra, 9 females from Acacia brachystachia, 20.iv.1997 (LAM 3163).

Comments. This species is related to S. kirrhos and S. moneres, but has short pronotal posteromarginal setae. Moreover, many of the available specimens are remarkable in having four pairs of posteromarginal setae on the sternites, a character state that otherwise has been seen only in a few individuals of S. tenor .